Photoflash lamp



Jan. 13, 1942.

v 55 ATTORNEY PHOTOFLASH LAMP Filed Jan. 26, 1940 M. J. N. DE MARGITTAPatented Jan. 13, 1942 UNITED STATES PATENT 'OFFICE PHOTOFLASH MichaelJ. Neumann de Margitta, New York,

N. Y., assigner to Westinghouse Electric & Manufacturing Company, EastPittsburgh, Pa., a corporation of Pennsylvania Application January 26,V1940, Serial No. 315,739

- In Hungary September 5, 1939 10 Claims.

The invention relates to lamps, and especially to photoflash lamps.

An object of the invention is to provide a cheap and easily manufacturedphotoash lamp.

Another object of the invention is to provide a method of assemblingphotoilash lamps for quantity production. n

Other objects and advantages of the invention will be apparent from thefollowing description and drawing, in which:

Fig. 1 is a cross-section through a preferred embodiment of theinvention.

Fig. 2 is a modification of the embodiment in Fig. 1.

Figs. 3 and 4 are cross-sectional views of a 'l 2g 24 therethrough, forthe application of a heatpreferred type of mold for forming one end ofthe flashlamp having conductors sealed therein.

Figs. and 6 are cross-sections through a preferred type of mold forforming the other end of the lamp.

Fig. '7 is a cross-sectional view on linesVII- VII of Fig. 4. X

The present commercial type of photoilash lamp has glass casings whichhave to be carer fully handled, formed and sealed with a resultant pricewhich is high in comparison with the cost of the filament. I

Furthermore, these gl'ass case ilashlamps always present a possibledanger of Vbroken glass, especially in 'the disposal of them. It 1s oneoi the objects of my invention to provide a photoash lamp having acasing in which there will be no danger of broken glass from handling,use or disposal, and also one that can be very easily and cheaplymanufactured, as illustrated on the drawing, and described below.

In Fig. 1 I have illustrated a preferred type of photoflash lamp havingtwo conductors Il and II therein, with van igniting element I2, such asa filament coated with zirconium, aluminum or phosphorous powder, and alling of combustible material I3, such as a foil,V or a bundle of linewires of aluminum or magnesium. The casing I4 in my preferredembodiment, isv an integral piece of plastic material. These plasticmaterials comprise the group of cellulose acetates. phenol-formaldehydeand urea-formaldehyde resins, casein, pyroxylin, shellac, rubber, acryland vinyl compounds having a' translucency or transparency suitable forthe passing of light material because it is tough, hard to burn and canstand careless handling. I do not prefer .the cellulose that has to beconstantly protected' by a special casing except when actually madeready for use.

In Fig. 3 I have illustrated the rst step in the preferred preparationof my flashlamp. A twopart mold is disclosed in which the upper part I5has a cylindrical opening I6 of the desired outside diameter of thephotoflash lamp extending therethrough, except that the lower portion I1of the cylindrical hole I6,-is gently tapered to the desired contour ofthe lower portion of the lamp. The very bottom portion of the lamp.-however, isformed by the contour I8 in the upper portion of the lowermold I9. The lower mold I9has two centrally located openings 20 and 2|for the passage of the conductors 22 and 23 into the space I 6. Thelower mold has passageways ing medium, which is preferably steam,although other forms of heating energy might be supplied to the lowermold. The upper mold has passageways 25 therethrough, especially .for acooling g5 liquid such as water, although at other times $0 plasticmaterial 26, such as cellulose acetate, is

inserted in the upper mold. This plastic material may be convenientlyinserted in the form o! a-hollow tube with an outside diameter to fit inthe hole I6, and thus substantially coincide with the desired diameterof the completed ashlamp. A forming member 21 is now inserted into thecentral portion of the opening I6. This forming member 21' has a shapeand diameter corresponding tothe shape and inner diameter of thecompleted ilashlamp. In the center of this forming member are two holes28 and 29 for the purpose of holding the conductors 22 and 23 inposition while the lower end of the ilashlamp is being formed. Thebottom portion 28' and 29" f 5 of these holes are slightly enlarged toguide the conductors into the. openings when the inner member 21 islowered. This member 21 is low-v ered the distance (a), illustrated inFig. 3, and then lthe two conductors 22 and 23 are pushed up i'nto theseholes 22 and 29, as illustrated in Fig. 4.

Steam is then admitted into the passageways 24, so that thelower mold Ilbecomes very hot. At the sametime, a sleeve 29 is lowered around theforming member 21 and presses upon the uptherethrough. Cellulose acetateis my preferred 65 per end 3l of the cylindrical Plastic tube S0 thatits lower edge 32 is pressed downward into the ,heated space I8 at thetop of the lower mold I9.

able pressure is exerted on the plastic material to completely ll thisspace by the sleeve 3U which fills the clearance space between the innerforming member 21 and the outer diameter of the opening I8 in the uppermold. This sleeve presses down the plastic tube the distance (c)illustrated in Fig. 4.

The slight clearance between the conductors 22 and 23 and the rim of theopenings 3l) and 2l permits the escape of the imprisoned air, but thisclearance is not sufficient to allow the plastic material to flowtherein.

The steam is then shut off andcooling material sent through thepassageways 25 in the upper mold I5, and also preferably throughpassageways 34 in the inner forming member 21. The plastic material 26under the in duence of this cooling means through 25 and 34, hardensinto a closed end tube sealed about the conduc-, tors 2B and 29. Thelower mold I9 is removed, and the inner forming member 21 and sleeve 3Draised and the partially formed closed end tube 26, with its conductorssealed therethrough, removed from the upper mold I by pressing upon thenewly formed projecting portion 33, illustrated in Fig. 4.

An alternative method is to place or pour softened plastic materialbetween the heated surfaces of the former and mold members of Fig. 4and, after pressing into shape, to cool and remove the tube andconductors sealed therethrough.

A combustible material I3 is inserted in this tube and the ignitingmeans I2 connected across the topportion of the conductors. If desired,a thermal shield 34, such as an asbestos disc or mica disc, may besecured to the top of the conductors. The appearance oi' the tube is nowthat of Fig. l except that the top portion of the container I4 is thatillustrated in dotted lines. 'Ihe tube is then preferably inserted intheV apparatus illustrated in Fig. 5, with the open end 35 of the tubefacing downward in an upper mold 36. The central opening 31 of the mold,in which this tube has been inserted, has a curved bottom portion 38corresponding to the desired'shape oiA the top portion of the tube,except for the very top portion whose contour 39 is made' in the lowermold 40.

Aside opening I4I in the upper mold 36 extends Fs' to a two-way valveopening to an exhaust port 42 and also to an oxygen or other active gasAsupply port 43. The upper mold 36 contains passageways 44 therethroughfor a cooling liquid,l

such as water. and the lower mold 40 has passageways 45 therethrough,for a heating medium whichfin this case, is that of .an electric ,heateroxygen supply is passed in by means of the port 43 to fill the innerportion of the container to any desired pressure of below, at, or aboveatmospheric pressure.

The heating means at 45 of the tube becomes soft because of the presinthe lower mold is). then actuated and the tube pressed downward sure andheat. The softened plastic is then shaped by the hot walls of the moldinto a closed end`46, illustrated in Fig. 6. The heating medium in isshut off and a cooling medium In Fig. 2 I have illustrated amodification in which the lower portion of the lamp 41 is molded as thescrew-threaded base with a central conductor 48 extending therethrough.Asbestos or mica discs 50 and 5I help support these conductors in thetube with the combustible material I3 around them. A conductive metalcoating 52 is then sprayed over the screw mold 49 down to the portion 53where the wireY 49 extends through the casing.

Fig. 2 illustrates a very cheaply formed screw-l threaded type offlashlamp.

Although I have described certain embodiments and also certain steps inthe manufacture of these embodiments, it is apparent that manymodifications and changes in the form of the vdevice and in the stepsoi' manufacture can be made. Accordingly, I desire only such limitationson my invention as are necessitated by the spirit and scope of thefollowing claims.

I claim:

1. The method of making a fiashlamp which comprises inserting a plasticmaterial in a mold, placing conductors therein, applying heat to theplastic material, pressing the plastic material into a closed end tubeabout said conductors, inserting igniting means across said conductorsand combustible material in said tube. exhausting the tube, filling thetube with a combustion-supporting gas, and sealing the open end ofthetube.

2. 'I'he method of making a ashlamp which comprises inserting a plasticmaterial in a mold, placing conductors therein, applying heat to theplastic material, pressing the plastic material into igniting meansacross said conductors and combustible material in said tube, exhaustingthe tube, lling the tube with a combustion-'supporting gas at more thanatmospheric pressure, and sealing the open end of the tube.

3. The method of making a 'flashlamp which comprises insertingconductors in an open end of a tube of plastic material, heating saidopen end of plastic material to flow about said conductors and be sealedthereto to form a closed end tube, connecting igniting means to saidconductors, placing combustible material in said tube, inserting acombustion-supporting gas in said tube -and sealing the open end of saidtube.

4. The method of making a flashlamp which comprises inserting a tube ofplastic material in a mold. locating conductors at one open end oi' saidtube, applying heat to the region of said conductors, pressing said tubeinto said heated region to seal the plastic material into a closed `endtube about said conductors, connecting an igniting deviceto saidconductors within the tube, placing combustible material around theigniting device. and sealing the open end of the tube.

`5. The method of making a flashlamp which comprises placing a tube ofplastic material in a cylindrical mold. locating conductors in thebottomyof said mold, applying heat to the bottom portion of said moldand pressing downward on said tube to mold said plastic material aboutsaid conductors, connecting an igniting device to said mosphere fromsaid tube and replacing it with a d combustion-supporting gas,heatingthe end ofconductors within said tube, placing combustiblematerial about said igniting device and sealing the open end of saidtube.

6. The method'of making a ilashlamp which comprises placing a tube ofplastic material in a cylindrical mold, inserting a former within saidtube, holding conductors by said former, applying heat to said tube tomold one end of the tube into a closed end tube between the mold andformer and sealing'the conductors through said closed end, connecting anigniting means to said conductors within the tube, surrounding theigniting means with a combustible material and sealing the open end ofsaid tube.

7. The method of making a ashlamp which comprises placing a tube ofplastic material in a cylindrical mold, having the desired contour ofthe outside of one end of the lashlamp, inserting a former having thedesired contourof the inside of one end of the ashlamp, holdingconductors extending through said former and mold, applying heat andpressure to said tube to form a closed end of the tube between the moldand former and sealing the conductors therethrough,

said tube and sealing the open end thereof in said mold.

9. The method of making a ilashlamp which comprises sealing conductorsthrough the closed end of a tube of plastic material, connecting anigniting device to s aid conductors within said tube, placingcombustible material about the igniting device, inserting the open endof said tube' within a tight-tting mold; exhausting the atmosphere fromsaid tube and replacing it with a combustion-supporting gas at greaterthan atmospheric pressure, heating the end of said tube, and sealing theopen end thereof in said mold.

10. The method of making a flashlamp which lcomprises placing a tube ofplastic material in a cylindrical mold having the desired contour of theoutside of one end of the flashlamp, inserting a former having thedesired contour of the inside of one end of lthe ashlamp, holdingconductors extending through said former and mold, applying heat andpressure to said tube to form a closed end of the tube between the moldand formersealing the conductors therethrough, removing the former andthen the tube from the mold, connecting an igniting device to saidconductors within the tube, placing combustible material about saidigniting device and sealing the other end of said tube by inserting vtheend in a tight-tting mold, heating the plastic edge until.

it shapes into a closed end conforming to the contour of the mold,hardening the tubev and withdrawing it from the mold.

MICHAEL J. NEUMANN DE MARGITIA.

